<section>
    <ion-item>
        <ion-label>用户名</ion-label>
        <ion-input [(ngModel)]="username"></ion-input>
    </ion-item>
    <ion-item>
        <ion-label>密 码</ion-label>
        <ion-input type="password" [(ngModel)]="password"></ion-input>
    </ion-item>
    <ion-button expand="block" (click)="submit()">登录</ion-button>
</section>